Solar crunch time! Please review my plan.

[Chilepalace]

I would like begin my first post with a big thank you to all who have shared their knowledge and experience on this forum. Without that, I probably wouldn't be entering the solar jungle!

I hope you will take a look at my plan,(will try to keep it short), and alert me to any big mistakes I am about to make.

The rig: 27' 5er, 2 Trojan T-105 batteries. Lots of dry camping, however our power needs are minimal. No plans for a large inverter or power hungry appliances. LED's already installed. Usually camp in warm, sunny places, often at 11,000ft. elevation.

The equipment:
Solar Cynergy 300W kit from Solarblvd. $415/free shipping.
Includes:
2 150W mono panels
Solar Cynergy 20amp controller(probably not use).
40' of 10Ga. cable w/mc4 connectors, 2 mc4 Y connectors.
8 'Z' brackets(won't use).

Trimetric SC2030 controller kit from solarseller.com. $340 w/shipping.
Includes:
30amp PWM Controller and 2030RV monitor.
500amp shunt.
Monitor wiring harness and temp. sensor w/connectors.

Battery cables,fuses, disconnects, panel mounting hardware: <$200? So maybe do this for just under $1000. Worth it?

My main questions for all of you:
Is the above controller & monitor a good choice for my system?
Would an MPPT controller justify the extra cost? I have been trying to research the Tracer 4215Bn with Mt50 remote monitor. Haven't had any luck finding adequate info.(or suppliers) on these units.

Wire size: Approx. 12' run from panels to controller, is 10 ga. supplied in the kit adequate? 4' controller to batteries, 4ga. welding cable OK?

Thank you for any comments/suggestions you care to share.

[reed_cundiff]

grizzzman - your guess is quite good. And over at Northern Arizona we have a couple of similar snarks. Disagree (as in say something nice about LFP) and you are off the island. It is not worth the effort to get involved.

We are currently mootchdocking (a nice portmanteau of mootching and boondocking) at older son's place at 7800' in mountains of northern NM. He is entirely off-grid, he and grandson built a pad for us with a sewer trap, and he now has a good well (solar powered). Solar insolation is great as we have had up to 1400 W to controller (TriStar MPPT-45) and 8100 W-hrs harvest in one day (we don't usually use that much but I ran the water heater on AC all day to see what might happen and the solar kept up with it - and the fridge).They have two great cats, three great dogs, one amusing semi-feral Peahen, 10 curious Barred Rock chickens (do not leave door of RV open) and two cranky Llamas. We had planned trip to Newfoundland via the Trans-Labrador and ferry from Blanc Sablon but Elaine needs knee surgery this summer.

Pianotuna- It is still a lot heavier. I just googled around a bit and I came up with 72# per 100 amp-hours and I was going with 50% SOC which would be 144# per 100 usable amp-hours. Your calculations have it about 3 times as heavy as opposed to 4 times. My knowledge of LFP is anecdotal from our experience and discussing with others.
Reed and Elaine

[grizzzman]

reed cundiff wrote:
bka0721

I think that an "excess" of solar is a good idea since there are a lot of days even in New Mexico (where we are currently) that are not the best for solar. We were still getting 100 W or so with 15 to 20 cm of snow on the panels. We have a lot of solar and a lot of LFP. Another advantage to LFP is no Peukert Disadvantage, so the charging rate is almost linear.

Some moderator on Solar Panel Talk was ranting that no one has enough battery storage to last 5 days without sun. I wrote that we had that capacity and so he wrote back that we obviously had more capacity than was required. He is a cranky lad and most snarky. He is also quite full of himself.
Reed

Hi ya Reed. Let me guess sunking? :R

[pianotuna]

Hi Reed,

four l-16 lead acid Surrette will provide about 5000 watts usable and weight is around 492 lbs.

Please continue to share your experience and knowledge of LI batteries.

[reed_cundiff]

Don - there are a lot of advantages to LFP and two major ones: cost and possibility of damage at high rate of charge below 0 C. As noted above, weight is critical to us. Industrial standard for lead acid is is 72# (33kg) per 100 amp-hr (12 V nominal)(http://www.powerstream.com/Size_SLA.htm) so b may be hauling 1100 pounds (511 kg). We have 7 kW-hr of usable which would be about 14 kW-hr (1170 Amp-hr at 12 V) of lead-acid which is a bit less than b's usable. I feel pedantic about putting this in to you two but a few folks that read these fora don't know the difference between usable and stated Amp-hr (kW-hr).

b - hope paths cross but not with to many young Grizzlies like at Chewing Black Bones.

Reed and Elaine

[pianotuna]

Hi Reed,

My interpretation of the advantage of LI batteries is there is no need to get to 100% state of charge. So many lead acid cells die from that requirement not being met.

[bka0721]

Reed, you are sooooooo right about boosting the size of the Battery bank and the problems it would have been for me, if I had responded to that urge. As it is now, my total battery bank/s is; 1,460 (1,160/300) AmpH complementing, 1,860w of solar (1,560w/300w). As you know, I have two banks. When swapping out my batteries earlier this year I seriously thought about boosting it with 2 more 6v batteries (232 AmpH). But then I would be back to the same issue I had before I boosted (tuned) my solar panel wattage/quantity. But, I knew the issues I would be creating by having more battery bank than my solar could service. As you have seen me write about often, in this forum and my articles, balance is key. When a weekender can just return home and plug in and it is all taken care of. But for extended adventurers/Fulltimers and long vactioners, they need to work within the plan.

Yes, I'll be in touch as I am back working for the National Parks, after a 35 years break.

b

[reed_cundiff]

bka0721

It was great meeting you last year

We are at older son's place in mountains near Las Vegas, NM. This is a great place at 7800'. They are getting much needed rain.

Really impressed by all that you are putting on your rig. Of course if one gets a lot of solar, then you think of getting more battery capacity, and when you get more battery capacity ....

We will be going to visit younger son in Fort Collins and should be there around 3 June. Will leave rig at older son's place since we need to be back in Albuquerque the middle of June. Will then head back to Fort Collins with rig to spend time with son and family. Let us know where you are staying via message on Facebook and if you are in Colorado, we would enjoy dropping by. We still have not seen your rig.

Reed and Elaine

[bka0721]

Hi Reed! I am entrenched in my Ranger Station for the summer writing as there is no cell or internet here in this remote location. It will open for the summer, next weekend. Why I am saying this is that it has been raining here EVERY day for the last 2 weeks I have been here, as well as in Boulder Colorado the 16 days I was there. With excess solar I have not had a single day of where I needed additional charging support, thus the reason I feel to build a system in excess of the battery bank. Much like one just gets a tarp with a hole in the center to gather water from a wider area into the catch bank, while in the desert or on an island. My days of limping through cloudy periods are long gone. Where I use to think have a HUGE battery bank was the trick, and is for weekend use, I have learned that is not neccessarily for uses such as you and I, as well as others fulltiming, or extended adventurers in their RVs. No matter what type.

Glad you are back in the states. Hope our paths cross again, in 2015.

b

[reed_cundiff]

bka0721

I think that an "excess" of solar is a good idea since there are a lot of days even in New Mexico (where we are currently) that are not the best for solar. We were still getting 100 W or so with 15 to 20 cm of snow on the panels. We have a lot of solar and a lot of LFP. Another advantage to LFP is no Peukert Disadvantage, so the charging rate is almost linear.

Some moderator on Solar Panel Talk was ranting that no one has enough battery storage to last 5 days without sun. I wrote that we had that capacity and so he wrote back that we obviously had more capacity than was required. He is a cranky lad and most snarky. He is also quite full of himself.
Reed

[bka0721]

BFL13 wrote:

pianotuna wrote:
Hi Reed,

I don't always agree with BFL13, but I have a LOT of respect for the tests he has done for all of us. I'd be proud to call him a friend.

reed cundiff wrote:
Well at least folks are being polite here, something that does not always happen on other fora.

Reed and Elaine
Solar autonomous for two years and delighted.

PT, you are cute too! 🙂

Looking at Surrettes--wow, bring money! 😞

http://www.wegosolar.com/brands.php?brand=Surrette

Like you guys, I will pay more attention when information is being shared by you 3, than most here. Plus the personality you 3 bring to your sharing, as well.

One thing I don't remember seeing discussed, is the balance of banks and solar is important with longevity of the battery bank While having a larger battery bank is nice, the issue becomes if you don't have a large enough solar harvesting to reach your 3 stages, to Float, your batteries will slowy deteriorate faster than if they were properly maintained and monitored. That is where a balance, or tuning of your Power Plant is important. For me, I have an excess of solar panels due to my need to make up for the 60%-/+ of PV loss in the winter and colder months. For the weekender my program looks excessive, and it is for their use. But the plus side I can utilize this excess for addtional power during the warm months to run my Air Conditioner, if I were want to stay in warmer climes for the summer months. Again, a well tuned solar system is important for the individual's uses and location.

b

[Fisherguy]

pianotuna wrote:
Hi Reed,

I don't always agree with BFL13, but I have a LOT of respect for the tests he has done for all of us. I'd be proud to call him a friend.

reed cundiff wrote:
Well at least folks are being polite here, something that does not always happen on other fora.

Reed and Elaine
Solar autonomous for two years and delighted.

We Canadians are the friendly sort eh? 😉

[reed_cundiff]

pianotuna

We have LFP not LPo.

Manzanita Micro is almost entirely EV. We may be the only non-EV battery suite they have ever sold. I talked with their manager on phone and he said they could be charged at much lower temperatures than other LFP formulations but I am not about to find out the hard way. When we left the rig at son's place where it did get cold, the battery suite probably never went down more than 5% (-400 W-hr) so any charge rate was quite low. I think the problem is at high C charge rates which is not a solar problem (would that it were).

I would think that NASA quality batteries/cells are way beyond our piggy banks.

Reed and Elaine

[pianotuna]

Hi Reed,

I looked at the Manzanita Micro site. I could not find cold weather specifications and I'm afraid my piggy bank would be badly broken, even for 500 amp-hours.

[NinerBikes]

OP

I'd look at polycrystalline cells instead of monocrystalline cells for your application. I'll let the guru's tell you why.